Spacer device for inhaler

ABSTRACT

A spacer device for an inhaler is made of a non-metallic antistatic material, preferably polyamide. The device may comprise two frustoconical members joined at their wider ends, with an inlet and outlet at, respectively, the two narrower ends. A measured dose of medicament is injected through the inlet, and then inhaled from the chamber through the outlet.

[0001] The invention relates to a spacer device for an inhaler for oraladministration of a medicament by inhalation.

[0002] There are essentially two known types of inhaler in common use.In the fist type, a jet of gas having the dose of medicament therein isproduced and is inhaler is used by directing the jet into the throatwhilst inhaling. The gas is usually an aerosol propellant and themedicament is a fine powder. Whilst thee inhalers are excellent atdelivering predetermined doses of medicament, there is a tendency forthe powder to be deposited in the mouth and throat of the user, and thusnot reach the lungs. Indeed, really successful use of these inhalersrequires not only practice but good coordination between a patient'sbreathing and actuation of the device. The efficiency of administrationby this route also depends on the shape and dimensions of the patient'soral cavity.

[0003] The second type of inhaler is essentially simpler and essentiallycomprises a dose of powdered medicament which is withdrawn from thedevice suspended in air by the patient inhaling through the device. Adrawback of these devices is the variability of the inhalation air flowwhich, in turn affect the carry of powder from the device and thevelocity of inhalation. Powder deposit in the mouth and throat is commonuntil the patient is well-practised in use of the device.

[0004] With a view to reducing these problems, it has been proposed toprovide a spacer device between the medicament source and the mouth ofthe patient. The spacer device essentially comprises a chamber with aninlet for receiving the medicament suspended in gas (eg. air orpropellant), and an outlet through which the medicament suspension isdrawn by inhalation of the patient The use of a spacer device improvesthe efficiency of inhalation of the medicament into the lungs.

[0005] Spacer devices are known which are made of metal or ofpolycarbonate. Metal devices are not preferred and polycarbonate devicesare the more common. We have found, however, that there is a drawbackwith polycarbonate devices in that the powdered medicament becomesdeposited on the inner walls of the chamber, thus reducing the doseinhaled by the patient. We have investigated this phenomenon and havefound that a similar effect is shown when a spacer is made of variousother plastics materials including polypropylene, polystyrene and lowdensity polyethylene. Further, we have found that whilst this problemcan be reduced by including an antistatic agent in the plasticsmaterial, the improvement is only short-term: the antic effect of theagent soon wears off.

[0006] We have now found that this problem can be overcome by using anon-metallic material for the spacer device, which is inherentlysubstantially antistatic. We have found that, surprisingly, there aresuch plastics materials from which spacer devices can be made. We havefound, in particular, that plastics materials which absorb and retainmoisture are especially suitable. Among the most preferred materials arethe polyamides: routine trial and experiment will reveal whether or notany particular material is useful.

[0007] Accordingly, in one aspect the invention provides a spacer devicefor the oral administration of a volatile medium containing amedicament, which device comprises a chamber having an inlet to admit ameasured dose of medicament and an outlet to be received in the mouth,wherein the chamber is made of a non-metallic antistatic material.

[0008] In another aspect, the invention provides an inhaler fordispensing a measured dose of a medicament in a volatile medium, aspacer device for receiving the medium, and means whereby the user caninhale the said medium from the spacer device, wherein the spacer deviceis made of a non-metallic substantially antistatic material.

[0009] The invention also includes the use of a non-metallic antistaticspacer device for the inhalation of a particulate medicament in avolatile medium.

[0010] The invention firer includes a method of administering a dose ofa fine particulate medicament suspended in a gas, which comprisesinjecting said dose into a non-metallic antistatic chamber, and inhalingthe dose from the chamber.

[0011] The spacer devices of the invention can be of various shapes andconstructions but we prefer the chamber to comprise two frustoconicalmembers assembled together coaxially at their divergent ends, said inletand outlet being respectively at the opposed convergent ends.Preferably, the divergent end of one member is received in the divergentend of the other member to provide a substantially air-tight seal.Preferably also the divergent end have complementary stepped surfaces toprovide a close air-tight fit. Locking me can be provided to lock thetwo members together in the assembled condition.

[0012] In order that the invention may be more fully understood, oneembodiment of spacer device of the invention will now be described, byway of example only, with reference to the accompanying drawings,wherein:

[0013]FIG. 1 is a plan view of the assembled spacer device embodimentaccording to the present invention;

[0014]FIG. 2 is a longitudinal axial sectional view of the spacerdevice, the cones being dismantled;

[0015]FIG. 3 is an end view in direction A of FIG. 2;

[0016]FIG. 4 is an end view in direction B of FIG. 2; and

[0017]FIG. 5 is a schematic illustration of the spacer device positionedon a medicament container (eg. pump).

[0018] Referring to the FIGS. 101 and 102 are two conical members madeof anti-static material defining chamber 120. The conical members 101and 102 are assembled at their divergent ends, 103 and 104,respectively. The convergent end 105 of the conical member 101 is aninlet and is adapted to connect with a pumping device (not shown)containing the medicinal composition. The convergent end 106 of theconical member 102 is the outlet and is adapted to be inserted into themouth of a patient. The inner surface at the divergent end of theconical member 101 is provided with stepped rings 107, the steps beingdirected towards the diverging end, and the outer surface at thedivergent end of the conical member 102 being provided with steppedrings 108 corresponding to the stepped rings 107. A stop 110 at thedivergent end of the conical member 102 restricts insertion of theconical member 101. The conical members 101 and 102 are provided withlocking mean 109, such as a notch and the projection to ensure that thetwo members have been properly assembled.

[0019] In use, inlet 105 is connected to an aerosol medicament reservoir(121) for example, and a dose of inhalant suspension is pumped intochamber 120. The patient then places outlet 105 in the mouth and inhalessteadily to draw the suspension into the lungs.

[0020] A polyamide spacer of the invention was compared with variouscommercially available polycarbonate and metallic spacers using the fineparticles assessment test (Aerodynamic assessment of fine particlefraction as per BP Addendum 1996 using apparatus A and ten doses).

[0021] This test for fine particle assessment by twin impinger gives anin vitro estimate of the distribution of the drug in the humanrespiratory tract. The apparatus comprises two parts. The first part isan upper impingement chamber which corresponds to the oropharyngealcavity (Stage 1) and has a nominal particle size cut-off of 6.4 μm. Thedrug deposited here is regarded as non-respirable since it correspondsto drug deposited in the mouth or the throat. The second part is a lowerimpingement chamber (Stage 2) which corresponds to the lungs. The amountof drug deposited here of particle size less than 6.4 micron,corresponds to the amount of drug which would be available immediatelyat the site of action i.e. in the lungs, and is considered to be therespirable fraction.

[0022] The test was conducted using a Budecourt 100 inhaler at 100 mcgdose, fitted with a series of different spacers. The spacer according tothe invention was as illustrated in the drawings hereof and was made ofpolyamide. The results were as follows: Prior art spacers D Spacer of AB C polycarbonate Retention in invention Ektar polycarbonate metal(composition) Actuator 15.06 13.92 10.13 18.73 8.91 Spacer 16.66 59.6445.95 26.52 49.01 Stage 1 8.87 9.14 8.33 13.14 6.44 Stage 2 59.41 17.3035.59 41.61 35.64

[0023] The numbers are the percent by weight of particulate depositedafter ten “inhalations”.

[0024] The results show the advantages of the spacer of the inventionboth as to the much lower deposition of solids in the spacer itself andthe much higher deposit in Stage 2.

1. A spacer device for the oral administration of a volatile mediumcontaining a medicament, which device comprises a chamber having aninlet to admit a measured dose of medicament and an outlet to bereceived in the mouth, wherein the chamber is made of a non-metallicantistatic material.
 2. A device according to claim 1, wherein thechamber is made of an antistatic plastics material.
 3. A deviceaccording to claim 2, wherein the chamber is made of polyamide.
 4. Adevice according to claim 1, 2 or 3, wherein the chamber comes twofrustoconical members assembled together coaxially at their divergentends, said inlet and outlet being respectively at the opposed convergentends.
 5. A device according to claim 4, wherein the divergent end of onemember is received in the divergent end of the other member to provide asubstantially air-tight seal.
 6. A device according to claim 5, whereinthe said divergent ends have complementary stepped surfaces to provide aclose air-tight fit.
 7. A device according to claim 4, 5 or 6, whereinlocking means are provided to lock the two members together in assembledcondition.
 8. An inhaler for dispensing a measured dose of a medicamentin a volatile medium, a spacer device for receiving the medium, andmeans whereby the user can inhale the said medium from the spacerdevice, wherein the spacer device is made of a non-metally substantiallyantistatic material.
 9. An inhaler and spacer device according to claim8, wherein the spacer device is as claimed in any of claims 1 to
 7. 10.The use of a non-metallic antistatic spacer device for the inhalation ofa particulate medicament in a volatile medium.
 11. The use according toclaim 10, wherein there is substantially little or no deposit ofmedicament on the inside of the device.
 12. A method of administering adose of a fine particulate medicament suspended in a gas, whichcomprises injecting said dose into a non-metallic antistatic chamber,and inhaling the dose from the chamber.
 13. A method according to claim12, wherein the chamber is in a device as claimed in any of claim 1 to7.
 14. A method according to claim 12, wherein the chamber isconstructed of polyamide.